EWXa

My CEL came on a couple of days ago. I went to Auto Zone and was told the CEL code is PO171 which indicates a lean condition.
In the collective experience here, what is the most likely cause? I am thinking O2 sensor or MAF sensor. Any ideas or recommendations, please.

Ernie

mb2008

Check hose connections and look at the MAF sensor. You can just pull it out and see if its dirty and spray it with crc maf sensor cleaner. Maybe try a good fuel injector cleaner since it's lean. Once the problem is fixed the light might stay on for a little while so it's not as easy as checking one thing then starting it up to see if the light is off.

easternshorebox06

I'm watching this as well. I've cleaned my MAF, replaced air filter and replaced PCV. cleared codes and PO171 comes on when coming to a stop (stop sign, parking lot, garage) for a small amount of time. Car is also hard to start after filling up tank. wants to cough and stall. 241,000 miles on it. once on highway, runs fine and no difference in gas mileage. had same code back around 110,000 miles and the MAF cleaning did the trick but this time seems to require more investigating.

jct

with that many miles you might want to do this lil maintenance to your idle air control valve

http://www.celicahobby.com/forums/ub...rly-Clean.html

easternshorebox06

Update: was getting the PO171 code primarily and occasional PO441 and PO455 with it (not always). It would give a fit when trying to start after filling up the tank also. I cleaned my MAF again, replaced PCV, air filter, and went through a can of Seafoam fuel treatement and two bottles of Lucas fuel additive over course of couple weeks and last Friday lights stay off. I liked to top off and may have done to much once so I made sure not to top off excessively anymore either. maybe dirty injector or vapor lock that cleared up? anyhow, no longer getting codes so all is good again.

2steptalon

Did you erase the code or did it go away by itself?

easternshorebox06

both. I was driving with code reader connected to see when code would typically show up and most consistent. I would erase after stopped or parked. Then after a couple days code(s) no longer re-appeared since last Friday. (knock on wood).